The goal of the proposed research is to increase the understanding of the role of fear and disgust in Blood-Injection-Injury (BII) phobia. BII phobia has typically been conceptualized as being mediated by fear. However, recent research suggests that disgust may also play a functional role in the avoidance of BII stimuli. The proposed research will be a two-part study investigating the acquisition of fear and disgust in BII phobia. Specific aims of the proposed research are to: 1) compare degree of responding and conditioning of fear and disgust in BII phobia; 2) determine predispositional or vulnerability variables that may contribute to the acquisition of fear and disgust in BII phobia; and 3) examine differences in the acquisition of fear and disgust in individuals with and without BII phobia. This research will provide an important contribution to the understanding of the emotions that mediate BII phobia, thus potentially providing a foundation for incorporating effective treatment strategies.